Artificial filaments and method of preparing the same



Patented Mar. 9, 1937 iTE STATES PATE'EI' ARTIFICIAL FILAMENTS AND METHOD OF PREPARING THE SAME tion of Delaware No Drawing. Application January 23, 1931, Serial No. 510,845

6 Claims.

This invention relates to the preparation of artificial filaments, yarns and the like and relates more particularly to the preparation of yarns having a pleasing appearance and improved textile properties.

An object of our invention is to prepare artificial filaments having improved appearance and other desirable properties and which contain a water-insoluble salt or oxide of bismuth. Other 10 objects of our invention will appear from the following detailed description.

It has been previously proposed to incorporate inorganic pigment-like material in artificial yarn to subdue the lustre and increase the opacity thereof. In commercial processes involving the use of such pigments, many considerations enter so that the choice of a commercially suitable pigment is quite difiicult. We have found that such pigment must have good covering power,

should not be injurious to health when it comes in constant contact with the human body, and preferably should be of light color. We have found that the water-insoluble compounds of bismuth meet these requirements.

Moreover yarns containing the pigment-like materials formerly proposed are quite abrasive and cut the guides, knitting needles and other parts of textile apparatus with which they come in contact. We have found that yarn containing the waterinsoluble bismuth compounds have but little more abrasive properties than yarn not containing such compounds. Moreover, such bismuth compounds are not injurious when brought in prolonged contact with the human 3:, skin, as is evidenced by the fact that they are even employed in cosmetics.

In accordance with our invention we prepare a artificial filaments containing cellulosic materials which have improved properties by incorporating therein a finely divided bismuth compound.

The filaments made or treated in accordance with this invention may be of low denier which are associated together toform yarn, or the filaments may be heavier such as bristles, artificial =15 horsehair and straw. Such filaments may be of the reconstituted cellulose type formed by the Chardonnet or cuprammonium process, but this invention is particularly applicable to filaments containing organic derivatives of cellulose such as organic esters of cellulose and cellulose ethers. Examples of such organic esters of cellulose are cellulose acetate, cellulose formate, cellulose propionate and cellulose butyrate, while examples of cellulose others are ethyl cellulose, methyl cellulose and benzyl cellulose. The filaments containing the organic derivative of cellulose may be prepared by dissolving the organic derivative in a volatile solvent such as acetone and extruding such solutions through fine orifices into an evaporative atmosphere, as in dry spinning, or into a precipitating bath, as in wet spinning.

As stated, we incorporate in the filaments a finely divided water-insoluble bismuth compound. Any suitable insoluble bismuth compound may be used, examples of which are bismuth oxychloride (BiOCl) and bismuth hydroxide (Bi(OH)3). If colored pigments are desired, the oxides or the sulfide of bismuth may be employed.

In one form of our invention the insoluble bismuth compound is incorporated in the dope or spinning solution containing the cellulose compound. Generally the amount of such bismuth compound added is from 0.1 to 10% of the weight of the cellulose compound present in the finished yarn. The bismuth compound is preferably in very fine form, the particles having a diameter of less than 0.1 to 5 microns and preferably less than 1 or 2 microns for increased covering power.

This fine size may be attained by grinding the bismuth compound either with water, oily materials such as mineral oil or diethylene glycol, or part of the spinning solution or the solvent used in the spinning solution in a ball mill or colloid mill. The ground material is then added to the solution of the derivative of cellulose and to which may also be added diethylene glycol, heavy white mineral oil, olive oil, castor oil or other oils. The spinning solution containing the pigment is then preferably thoroughly mixed and subjected to the usual filtration before spinning. However the addition of the water-inso1uble bismuth compound to the spinning dope at any stage of the filtration process or even after completion of filtration is not excluded.

In another form of our invention, the finely divided water-insoluble bismuth compound is incorporated in the yarns or filaments by treating such yarns or filaments after their formation either in the form of hanks or in the form of woven or knitted fabric with a suspension of such bismuth compound in the presence of a swelling or penetrating agent for the cellulosic material of which such filaments are composed which causes the insoluble bismuth compound to become disseminated throughout the filaments. Thus if the filaments are made of cellulose acetate, the swelling agent employed may be an aqueous solution of acetone, acetic acid, thiocyanates of sodium, potassium or ammonium, diacetone alcohol or any other suitable swelling agent.

Filaments or yarns made in accordance with this invention have a subdued lustre and increased opacity and covering power, the amount of which depends upon the fineness of the size of the insoluble bismuth compound particles and the amount employed. Yarns made in accordance with this invention have highly improved textile properties, as is shown by the fact that they can be knitted to form circular knit or warp knit fabrics having many wales and courses and which are free of distortions and pin holes. Moreover such yarns may be Woven to form fabrics which are free of warp streaks and Weft bars.

Yarns prepared by our method may be wound and twisted more readily and form cones or other packages which do not tend to collapse. Heavier filaments such as bristles, straw and the like when made in accordance with this invention have improved knotting properties.

Moreover yarns prepared by our method, unlike yarn containing the pigment-like material previously employed, do not tend to out to an appreciable extent the guides, reeds, knitting needles and other parts of apparatus with which they come in contact during textile operations.

In order further to illustrate our invention, but Without being limited thereto, the following specific examples are given.

Example I One (1) part by weight of an acetone soluble cellulose acetate is dissolved in three (3) parts by weightof acetone and to this is added fifteen thousandths (0015) part by weight of bismuth oxychloride (BiOCl) in a small amount of water or acetone preferably containing cellulose acetate. This dispersion may be obtained by grinding the bismuth oxychloride with the liquid, to which granules or fibres of cellulose acetate have preferably beenadded, in a colloid mill or ball mill so that the most of the particles have a size of less than 1 micron in diameter. While the commercial bismuth oxychloride may be used, we

' prefer to employ the form obtained by the addition of water to a solution of bismuth chloride in acid (preferably hydrochloric acid) and the drying of the precipitate so formed, as this product grinds more readily. The mass is thoroughly mixed and then filtered. The filtered solution is then extruded through the orifices of a spinneret into a drying evaporative atmosphere and the filaments are drawn off and twisted together to form yarn which is wound. The yarn so formed has all the desirable properties above described. 7

If desired olive oil or diethylene glycol or a mixture of the two, in amounts of l to 5% of the weight of the cellulose acetate present may be added to the solution of the cellulose acetate prior to spinning. Also instead of adding the finely divided bismuth oxychloride to the spinning solution before the filtration, it may be added after such filtration.

Example II The process of Example I is carried out with the exception that bismuth hydroxide, (Bi(OI-I) 3) is employed instead of the bismuth oxychloride.

It is to be understood that the foregoing description is given merely by way of illustration and that many variations may be made therein Without departing from the spirit of our invention.

Having described our invention, what we desire and claim to secure by Letters Patent is:

1. Delustered extruded artificial filaments, yarn or like artificial extruded products containing up to 10% of finely divided bismuth hydroxide.

2. Delustered extruded artificial filaments, yarn or like extruded products containing cellulosic material and up to 10% of finely divided bismuth hydroxide.

3. Delustered artificial filaments, yarn or like extruded products containing cellulose acetate and up to 10% of finely divided bismuth hydroxide.

4. A solution, suitable for the production of artificial filaments, yarns or like extruded products, comprising finely divided bismuth hydroxide in an amount up to 10% based on the weight of the filament base present.

5. A solution, suitable for the production of artificial filaments, yarns or like extruded products, comprising cellulosic material and finely divided bismuth hydroxide in an amount up to 10% based on the weight of the cellulosic mat rial present.

6. A solution, suitable for the production of artificial filaments, yarns or articles, comprising cellulose acetate and finely divided bismuth hydroxide in an amount up to 10% based on the weight of the cellulose acetate present.

CAMILLE DREYFUS. WILLIAM WHITEHEAD. 

